The Fulltone 2B is a clean boost pedal from Fulltone, designed by Michael Fuller as the boost channel of the Full-Drive 3 taken out on its own and fitted into the smallest enclosure possible1. It provides up to 20dB of gain boost1, enough to push an amp noticeably harder, and it adds a feature most clean boosts do not have: a germanium diode limiter circuit that tames harsh transients while making the tone bigger1.
Fulltone USA currently lists the pedal as the 2B Booster on its store, with shipping lead times given on each product page23.
What it does to your sound
A clean boost does one job: raise the guitar's output level without adding distortion of its own. The 2B does that with up to 20dB of gain, which Guitar World notes can significantly increase a guitar's output level1. Premier Guitar describes the character of the boost as "airy, detailed, and smooth," a wide-spectrum harmonic boost that is not too trebly4.
The part that sets it apart is the dynamics control. Guitar World calls it a unique dynamics function that improves responsiveness without overloading an amp's input1. Premier Guitar explains what is under the knob:
"This little knob controls a germanium diode limiter that softens transient spikes."
Turned clockwise, the dynamic knob gives a progressively more controlled and contained boost signal4. In practice that means you can run a high boost setting and keep pick attacks from spiking into harshness. Guitar World's reviewer found the tone stays attractively rich and warm without adding any harsh overtones1, and summed up the pedal's effect:
"The Fulltone 2B not only significantly boosts a guitar's signal, it also sweetens the tone thanks to its unique germanium diode limiter circuit, which tames harsh transients while making the tone bigger."
Controls and connections
The control set is minimal: a full-size gain knob and a mini pot for the dynamics setting of the germanium diode limiter circuit1. The input and output jacks are mounted out of the way on the front panel, along with the power jack1.
| Control | What it does |
|---|---|
| Gain (full-size knob) | Sets the boost level, up to 20dB1 |
| Dynamics (mini pot) | Dials in the germanium diode limiter, softening transient spikes; clockwise is more controlled and contained14 |
Power and buffering
The 2B runs on a 9 to 18VDC regulated Class 2 power supply, or on an internal nine-volt battery1. Premier Guitar notes the JFET Booster can be operated at 18V for extra headroom4, which suits players who want the full 20dB of boost to stay clean into a hard-pushed amp.
The 2B is not true bypass. Like the Full-Drive 3, when it is off it is a high-quality JFET unity gain buffer that drives long cable lengths and prevents tone-suck1. Premier Guitar adds that it works as a buffer whether on or off, making it what they call a superb post-fuzz, pre-delay buffer and boost on a busy board4. If you specifically want a pedal that disappears completely from the signal chain when bypassed, this is not that pedal; if you run long cables, the always-on buffer is the point.
Where it came from
The 2B is not an original circuit so much as a extraction. Guitar World describes it as essentially the Boost channel found in the Full-Drive 3 pedal, which Michael Fuller separately installed in the smallest enclosure possible1. Premier Guitar's 2026 review of the 2B JFET Booster says the same thing in different words: it is essentially the clean boost section of the excellent Full-Drive 34. Players who already know the Fulldrive 3 will recognize the boost side; the 2B gives it to you without the overdrive section.
What reviewers said
Both published reviews were positive. Guitar World's 2016 review gave the 2B a $104 street price and concluded that it boosts the signal and sweetens the tone through its germanium diode limiter1. Premier Guitar's 2026 review of the 2B JFET Booster was stronger still:
"Fulltone's new 2B is a great clean boost, in fact it's one of the finest I've ever used."
Premier Guitar tested it with a Rickenbacker 330, a Fender Jaguar fitted with Seymour Duncan "Jaguar Hot" pickups, a silverface Fender Bassman with Warehouse G12C/S speakers, a Vox Pathfinder, and a '72 Fender Champ4, so the verdict covers both single-coil and offset-style guitars into a range of amp sizes. The same review listed the street price at $103.204, essentially unchanged from the 2016 figure.
How it compares
Against a basic clean boost, the 2B's differences are the germanium diode limiter and the always-on buffer. The limiter gives it a dynamics control most boosts lack14, and the JFET buffer means it keeps working on your tone even when the boost is off14. For more on the category, see boost pedals and buffer pedals; for the pedal the 2B came from, see the Fulltone Fulldrive 3.
Videos
Guitar World
HaarGuitars
The Tone Unknown
Questions
Does the Fulltone 2B run on 18V?
Yes. The 2B accepts a 9 to 18VDC regulated Class 2 power supply, and Premier Guitar notes it can be operated at 18V for extra headroom. Running it at the higher voltage gives the boost more clean room before the signal runs out of space, which matters if you are pushing an amp hard.
Does the Fulltone 2B take a battery?
Yes. The pedal has an internal nine-volt battery, and the 9 to 18VDC power jack can be used instead of it. The input, output and power jacks are all mounted on the front panel, out of the way of the footswitch, which helps on a crowded pedalboard.
Is the Fulltone 2B buffered?
Yes. When the 2B is off it acts as a high-quality JFET unity gain buffer that drives long cable runs and prevents tone loss. Premier Guitar adds that it works as a buffer whether on or off, which makes it useful as a post-fuzz, pre-delay buffer and boost on a busy board.
How much boost does the Fulltone 2B give?
Up to 20dB of gain boost. Both Guitar World and Premier Guitar report the same figure, with Premier Guitar describing it as 20dB of JFET-driven, high-headroom boost that stays airy, detailed and smooth rather than harsh or overly trebly.
Is the Fulltone 2B JFET Booster a buffered pedal?
Yes. The 2B JFET Booster works as a buffer whether the pedal is on or off, so it keeps your signal strong through long cables even when you are not boosting. Guitar World describes the off-state buffer as a high-quality JFET unity gain design that prevents tone-suck.
Can the Fulltone 2B run at 18V?
Yes. Its power jack accepts a 9 to 18VDC regulated Class 2 supply, and Premier Guitar specifically notes it can be operated at 18V for extra headroom. An internal nine-volt battery is the alternative when you do not want to use a supply.
Sources (4)
- Review: Fulltone 2B Boost Pedal, Guitar World, 2016-01-21
- 2B Booster, Fulltone USA
- 2B Booster, Fulltone USA
- Quick Hit: Fulltone 2B JFET Booster Review, Premier Guitar, 2015-12-22
